Molecular sieve materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various types of hydrocarbon conversion. Molecular sieves that find application in catalysis include any of the naturally occurring or synthetic crystalline molecular sieves. Examples of these zeolites include large pore zeolites, intermediate pore size zeolites, and small pore zeolites. These zeolites and their isotypes are described in “Atlas of Zeolite Framework Types”, eds. W. H. Meier, D. H. Olson and Ch. Baerlocher, Elsevier, Fifth Edition, 2001, which is hereby incorporated by reference. A large pore zeolite generally has a pore size of at least about 7 Å and includes LTL, VFI, MAZ, FAU, OFF, *BEA, and MOR framework type zeolites (IUPAC Commission of Zeolite Nomenclature). Examples of large pore zeolites include mazzite, offretite, zeolite L, VPI-5, zeolite Y, zeolite X, omega, and Beta. An intermediate pore size zeolite generally has a pore size from about 5 Å to less than about 7 Å and includes, for example, MFI, MEL, EUO, MTT, MFS, AEL, AFO, HEU, FER, MWW, and TON framework type zeolites (IUPAC Commission of Zeolite Nomenclature). Examples of intermediate pore size zeolites include ZSM-5, ZSM-11, ZSM-22, MCM-22, silicalite 1, and silicalite 2. A small pore size zeolite has a pore size from about 3 Å to less than about 5.0 Å and includes, for example, CHA, ERI, KFI, LEV, SOD, and LTA framework type zeolites (IUPAC Commission of Zeolite Nomenclature). Examples of small pore zeolites include ZK-4, ZSM-2, SAPO-34, SAPO-35, ZK-14, SAPO-42, ZK-21, ZK-22, ZK-5, ZK-20, zeolite A, chabazite, zeolite T, gmelinite, ALPO-17, and clinoptilolite.
U.S. Pat. No. 4,439,409 refers to a crystalline molecular sieve composition of matter named PSH-3 and its synthesis from a reaction mixture for hydrothermal reaction containing hexamethyleneimine, an organic compound which acts as directing agent for synthesis of the MCM-56 (U.S. Pat. No. 5,362,697). Hexamethyleneimine is also taught for use in synthesis of crystalline molecular sieves MCM-22 (U.S. Pat. No. 4,954,325) and MCM-49 (U.S. Pat. No. 5,236,575). A molecular sieve composition of matter referred to as zeolite SSZ-25 (U.S. Pat. No. 4,826,667) is synthesized from a reaction mixture for hydrothermal reaction containing an adamantane quaternary ammonium ion. U.S. Pat. No. 6,077,498 refers to a crystalline molecular sieve composition of matter named ITQ-1 and its synthesis from a reaction mixture for hydrothermal reaction containing one or a plurality of organic additives.
U.S. patent application Ser. No. 11/823,129 discloses a molecular sieve composition designated as EMM-10-P, having, in its as-synthesized form, an X-ray diffraction pattern including d-spacing maxima at 13.18±0.25 and 12.33±0.23 Angstroms, wherein the peak intensity of the d-spacing maximum at 13.18±0.25 Angstroms is at least as great as 90% of the peak intensity of the d-spacing maximum at 12.33±0.23 Angstroms. U.S. patent application Ser. No. 11/824,742 discloses a molecular sieve composition designated as EMM-10, in its ammonium exchanged form or in its calcined form, comprising unit cells with MWW topology, said crystalline molecular sieve is characterized by diffraction streaking from the unit cell arrangement in the c direction. The crystalline molecular sieve is further characterized by the arced hk0 patterns of electron diffraction pattern. The crystalline molecular sieve is further characterized by the streaks in the electron diffraction pattern along the c* direction. U.S. patent application Ser. No. 11/827,953 discloses a crystalline MCM-22 family molecular sieve having, in its as-synthesized form, an X-ray diffraction pattern including a peak at d-spacing maximum of 12.33±0.23 Angstroms, a distinguishable peak at a d-spacing maximum between 12.57 to about 14.17 Angstroms and a non-discrete peak at a d-spacing maximum between 8.8 to 11 Angstroms, wherein the peak intensity of the d-spacing maximum between 12.57 to about 14.17 Angstroms is less than 90% of the peak intensity of the d-spacing maximum at 12.33±0.23 Angstroms.
The term “MCM-22 family material” (or “material of the MCM-22 family” or “molecular sieve of the MCM-22 family”), as used herein, includes:    (i) molecular sieves made from a common first degree crystalline building block “unit cell having the MWW framework topology”. A unit cell is a spatial arrangement of atoms which is tiled in three-dimensional space to describe the crystal as described in the “Atlas of Zeolite Framework Types”, Fifth edition, 2001, the entire content of which is incorporated as reference;    (ii) molecular sieves made from a common second degree building block, a 2-dimensional tiling of such MWW framework type unit cells, forming a “monolayer of one unit cell thickness”, preferably one c-unit cell thickness;    (iii) molecular sieves made from common second degree building blocks, “layers of one or more than one unit cell thickness”, wherein the layer of more than one unit cell thickness is made from stacking, packing, or binding at least two monolayers of one unit cell thick of unit cells having the MWW framework topology. The stacking of such second degree building blocks can be in a regular fashion, an irregular fashion, a random fashion, or any combination thereof; or    (iv) molecular sieves made by any regular or random 2-dimensional or 3-dimensional combination of unit cells having the MWW framework topology.
The MCM-22 family materials are characterized by having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 3.57±0.07 and 3.42±0.07 Angstroms (either calcined or as-synthesized). The MCM-22 family materials may also be characterized by having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstroms (either calcined or as-synthesized). The X-ray diffraction data used to characterize the molecular sieve are obtained by standard techniques using the K-alpha doublet of copper as the incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system. Materials belong to the MCM-22 family include MCM-22 (described in U.S. Pat. No. 4,954,325), PSH-3 (described in U.S. Pat. No. 4,439,409), SSZ-25 (described in U.S. Pat. No. 4,826,667), ERB-1 (described in European Patent No. 0293032), ITQ-1 (described in U.S. Pat. No. 6,077,498), ITQ-2 (described in International Patent Publication No. W097/17290), ITQ-30 (described in International Patent Publication No. WO2005118476), MCM-36 (described in U.S. Pat. No. 5,250,277), MCM-49 (described in U.S. Pat. No. 5,236,575), MCM-56 (described in U.S. Pat. No. 5,362,697), EMM-10-P (described in U.S. patent application Ser. No. 11/823,129) and EMM-10 (described in U.S. patent application Ser. No. 11/824,742). The entire contents of the patents are incorporated herein by reference.
It is to be appreciated the MCM-22 family molecular sieves described above are distinguished from conventional large pore zeolite alkylation catalysts, such as mordenite, in that the MCM-22 materials have 12-ring surface pockets which do not communicate with the 10-ring internal pore system of the molecular sieve.
The zeolitic materials designated by the IZA-SC as being of the MWW topology are multi-layered materials which have two pore systems arising from the presence of both 10 and 12 membered rings. The Atlas of Zeolite Framework Types classes five differently named materials as having this same topology: MCM-22, ERB-1, ITQ-1, PSH-3, and SSZ-25.
The MCM-22 family molecular sieves have been found to be useful in a variety of hydrocarbon conversion processes. Examples of MCM-22 family molecular sieve are MCM-22, MCM-49, MCM-56, ITQ-1, PSH-3, SSZ-25, and ERB-1. Such molecular sieves are useful for alkylation of aromatic compounds. For example, U.S. Pat. No. 6,936,744 discloses a process for producing a mono-alkylaromatic compound, particularly cumene, comprising the step of contacting a polyalkylated aromatic compound with an alkylatable aromatic compound under at least partial liquid phase conditions and in the presence of a transalkylation catalyst to produce the mono-alkylaromatic compound, wherein the transalkylation catalyst comprises a mixture of at least two different crystalline molecular sieves, wherein each of the molecular sieves is selected from zeolite beta, zeolite Y, mordenite and a material having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstroms.
A report by J. Ruan, P. Wu, B. Slater, L. Wu, J. Xiao, Y. Liu, M. He, O. Terasaki at the 15 IZA Conference in Beijing in 2007 disclosed ISE-MWW and ISE-FER materials, the former made from MCM-22-P material as starting material. U.S. Patent Application Publication 2005/0158238 to Tatsumi et al. disclosed MWW type zeolite substance. U.S. Patent Application Publication 2004/0092757 to Oguchi et al. disclosed crystalline MWW type titanosilicate catalyst. A report by W. Fan, P. Wu, S. Namba, and T. Tatsumi (J. Catalyst 243 (2006) 183-191) disclosed a new titanosilicate molecular sieve with the structure analogous to MWW-type lamellar precursor. J. Ruan, P. Wu B. Slater and O. Terasaki disclosed detailed structure of Ti-YNU-1 (Angew. Chem. Int. Ed., 2005, 44, 6719) similar to ISE-MWW.
These closely related materials may further be distinguished by comparing XRD diffraction patterns for d-spacing maxima corresponding to (002), (100), (101) and (102) reflections for both as-synthesized and calcined materials. The d-spacing maximum corresponding to (002) reflection is typically in the range from 14.17 to 12.57 Angstroms (˜6.15-7.05 deg 2-θ Cu Kα radiation). The d-spacing maximum corresponding to (100) reflection is typically in the range from 12.1 to 12.56 Angstroms (˜7.3-7.05 deg 2-θ). The d-spacing maximum corresponding to (101) reflection is typically in the range from 10.14 to 12.0 Angstroms (8.7-7.35 deg 2-θ). The d-spacing maximum corresponding to (102) reflection is typically in the range from 8.66 to 10.13 Angstroms (10.2-8.7 deg 2-θ). The following table (Table 1) summarizes the differences between MCM-22, MCM-49, EMM-10, MCM-56 and the titanosilicate material reported by Tatsumi et al. based on the existence and/or the feature of XRD diffraction pattern for d-spacing maxima corresponding to (002), (100), (101) and (102) reflections for both as-synthesized and calcined materials.
TABLE 1As-synthesizedCalcinedXRD(002)(100)(101)(102)(002)(100)(101)(102)MCM-22MCM-22-PMCM-22YesYesYesYesNoYesYesYesAll four peaks are resolved. A valleyPeak corresponding to (002) is notexists between (101) and (102), whereinvisible. All other three peaks arethe measured intensity corrected forresolved. A valley exists betweenbackground at the lowest point being(101) and (102), wherein theless than 50% of the point at the samemeasured intensity corrected forXRD d-spacing on the line connectingbackground at the lowest point beingmaxima for (101) and (102).less than 50% of the point at thesame XRD d-spacing on the lineconnecting maxima for (101) and(102).EMM-10EMM-10-PEMM-10YesYesNon-discreteYesYesNon-discreteBoth (002) peak and (100) peak arePeak corresponding to (002) is notresolved, wherein the peak intensity forvisible. Peak corresponding to (100)(002) is at least as great as 90% of theis well resolved.peak intensity of the d-spacingAnd,maximum for (100).peaks corresponding to (101) andFurther,(102) are non-discrete or exhibit apeaks corresponding to (101) and (102)valley but with measured intensityare non-discrete or exhibit a valley butcorrected for background at thewith measured intensity corrected forlowest point being not less than 50%background at the lowest point beingof the point at the same XRD d-not less than 50% of the point at thespacing on the line connectingsame XRD d-spacing on the linemaxima for (101) and (102).connecting maxima for (101) and (102).MCM-22As-synthesizedCalcinedfamilyYesYesYesYesNoYesYesYesmaterial asPeaks corresponding to (002) and (100)Peak corresponding to (002) is notdisclosedare well resolvedvisible. All other three peaks arein U.S.And,resolved. A valley exists betweenpatentpeaks corresponding to (101) and (102)(101) and (102), wherein theapplication are non-discrete peaks at a d-spacingmeasured intensity corrected forNo.maximum between 8.8 to 11background at the lowest point being11/827,953Angstroms, wherein the peak intensityless than 50% of the point at theof the (002) is less than 90% of the peaksame XRD d-spacing on the lineintensity of the (100).connecting maxima for (101) and(102).MCM-49MCM-49-PMCM-49NoYesYesYesNoYesYesYesPeak corresponding to (002) is notPeak corresponding to (002) is notvisible or as a shoulder peak. Peakvisible or as a shoulder peak. Peakcorresponding to (100) is well resolved.corresponding to (100) is wellAnd,resolved.peaks corresponding to (101) and (102)And,are resolved or exhibit a valley but withpeaks corresponding to (101) andmeasured intensity corrected for(102) are resolved or exhibit a valleybackground at the lowest point beingbut with measured intensity correctednot greater than 50% of the point at thefor background at the lowest pointsame XRD d-spacing on the linebeing not greater than 50% of theconnecting maxima for (101) and (102).point at the same XRD d-spacing onthe line connecting maxima for (101)and (102).MCM-56MCM-56-PMCM-56NoYesnon-discreteNoYesnon-discretePeak corresponding to (002) is notPeak corresponding to (002) is notvisible. Peak corresponding to (100) isvisible. Peak corresponding to (100)well resolved. Peaks corresponding tois well resolved. Peaks corresponding(101) and (102) are non-discreteto (101) and (102) are non-discrete orscattering.exhibit a valley but with measuredintensity corrected for background atthe lowest point being not less than50% of the point at the same XRDd-spacing on the line connectingmaxima for (101) and (102).MWWPrecursor (US Patent PublicationCalcined (US Patent Publicationmaterial20050158238, FIG. 4)20050158238 FIG. 2)YesYesYesYesNoYesYesYesAll four peaks are resolved. A valleyOnly three peaks are resolved. Aexists between (101) and (102), whereinvalley exists between (101) andthe measured intensity corrected for(102), wherein the measuredbackground at the lowest point beingintensity corrected for background atless than 50% of the point at the samethe lowest point being less than 50%XRD d-spacing on the line connectingof the point at the same XRD d-maxima for (101) and (102).spacing on the line connectingmaxima for (101) and (102).Ti-MCM-22Precursor (J. Catal., Table 1)Calcined (US20050158238 FIG. 1)YesYesYesYesYes/NoYesYesYesAll four peaks reported for Si/Ti = 106.All four peaks are resolved for Si/Tihigher than 70.Only three peaks for Si/Ti less than70.A valley exists between (101) and(102), wherein the measuredintensity corrected for background atthe lowest point being less than 50%of the point at the same XRD d-spacing on the line connectingmaxima for (101) and (102).
It is known that crystal morphology, size and aggregation/agglomeration, or new x-ray diffraction can affect catalyst behavior, especially regarding catalyst activity and stability.
The alkylaromatic compounds ethylbenzene and cumene, for example, are valuable commodity chemicals which are used industrially for the production of styrene monomer and co-production of phenol and acetone respectively. In fact, a common route for the production of phenol comprises a process which involves alkylation of benzene with propylene to produce cumene, followed by oxidation of the cumene to the corresponding hydroperoxide, and then cleavage of the hydroperoxide to produce equal molar amounts of phenol and acetone. Ethylbenzene may be produced by a number of different chemical processes. One process which has achieved a significant degree of commercial success is the vapor phase alkylation of benzene with ethylene in the presence of a solid, acidic ZSM-5 zeolite catalyst. Examples of such ethylbenzene production processes are described in U.S. Pat. Nos. 3,751,504 (Keown), 4,547,605 (Kresge) and 4,016,218 (Haag).
Another process which has achieved significant commercial success is the liquid phase process for producing ethylbenzene from benzene and ethylene since it operates at a lower temperature than the vapor phase counterpart and hence tends to result in lower yields of by-products. For example, U.S. Pat. No. 4,891,458 (Innes) describes the liquid phase synthesis of ethylbenzene with zeolite Beta, whereas U.S. Pat. No. 5,334,795 (Chu) describes the use of MCM-22 in the liquid phase synthesis of ethylbenzene.
Cumene has for many years been produced commercially by the liquid phase alkylation of benzene with propylene over a Friedel-Crafts catalyst, particularly solid phosphoric acid or aluminum chloride. More recently, however, zeolite-based catalyst systems have been found to be more active and selective for propylation of benzene to cumene. For example, U.S. Pat. No. 4,992,606 (Kushnerick) describes the use of MCM-22 in the liquid phase alkylation of benzene with propylene.
Existing alkylation processes for producing alkylaromatic compounds, for example ethylbenzene and cumene, inherently produce polyalkylated species as well as the desired monoalkyated product. It is therefore normal to transalkylate the polyalkylated species with additional aromatic feed, for example benzene, to produce additional monoalkylated product, for example ethylbenzene or cumene, either by recycling the polyalkylated species to the alkylation reactor or, more frequently, by feeding the polyalkylated species to a separate transalkylation reactor. Examples of catalysts which have been used in the alkylation of aromatic species, such as alkylation of benzene with ethylene or propylene, and in the transalkylation of polyalkylated species, such as polyethylbenzenes and polyisopropylbenzenes, are listed in U.S. Pat. No. 5,557,024 (Cheng) and include MCM-49, MCM-22, PSH-3, SSZ-25, zeolite X, zeolite Y, zeolite Beta, acid dealuminized mordenite and TEA-mordenite. Transalkylation over a small crystal (<0.5 micron) form of TEA-mordenite is also disclosed in U.S. Pat. No. 6,984,764 (Roth et al).
Where the alkylation step is performed in the liquid phase, it is also desirable to conduct the transalkylation step under liquid phase conditions. However, by operating at relatively low temperatures, liquid phase processes impose increased requirements on the catalyst, particularly in the transalkylation step where the bulky polyalkylated species must be converted to additional monoalkylated product without producing unwanted by-products. This has proven to be a significant problem in the case of cumene production where existing catalysts have either lacked the desired activity or have resulted in the production of significant quantities of by-products such as ethylbenzene and n-propylbenzene.
There is, therefore, a need for a new process of producing alkylaromatic compounds, especially mono-alkylaromatic compounds, with crystalline molecular sieve.